UPDATE: Test fire of Block 5 Falcon 9 at KSC's pad 39A! The brief firing of the rocket's nine main engines occurred at 7:25 p.m. Eastern. See full replay of the test fire (begins at 1:55:30) below. Read more about the mission here.

Watch live as SpaceX prepares to test fire its new Block 5 Falcon 9 rocket at Kennedy Space Center's pad 39A ahead of Monday's planned launch of a communications satellite.